PHP Help Please..

<form method="post" action="scriptname.php">
<input type="text" name="variable1"><br />
<input type="text" name="variable2"><br />
<input type="Submit" name="Submit" value="Submit">
</form>

$_POST['variable1']
$_POST['variable2']
$_POST['Submit']

<?php

// This checks if the user submitted.
// The word in parentheses must equal the value that you assigned the Submit button
if ($_POST['Submit'] == "Submit")
{
    // anything in here you do if the user submitted the form
    echo "Variable 1 is: ".$_POST['variable1']."<br />";
    echo "Variable 2 is: ".$_POST['variable2']."<br />";
}
else
{
    // This area is for if the user didn't submit. The else statement IS optional. It isn't needed.
    // You could just as easily leave it out and just have the form show no matter what.
}
?>

<input type="text" name="trees">

$_POST['trees']